Ran inverted spark, is the damage instant?
 

Ive been helping a friend with his MS. Uploaded PNP map and his car is running on 2 cylinders, igniter got hot and tacho stopped working. Checked settings and it was set to "inverted spark yes" so I changed it to None inverted and we changed the igniter. Still runs on 2 so is the damage already done to the coil pack?

Thanks

Probably.

Yea, it can be instant.

Was his car running fine before you uploaded the new MSQ? If it was, make sure you check all the settings and that they are right, but if it shows the same as your previous MSQ, then you might have blown it. I wouldn't know how to check the coils right of the bat with an DMM, maybe someone could chime in?

Also, maybe its about time you upgraded to COPs?

It was the first time its been run with the MS on.

At the moment COPs will only complicate things, just wanna get it running first.

It's not always instant, but if you lost tach then I'm guessing the damage has been done.

Is the replacement ignitor known to be a good one? If the tach isn't working then i would suspect the ignitor not the coil pack.
You can check the coil pack itself for spark visually by pulling the plug and reinstalling it in the coil wire, rest it near a grounded bolt on the valve cover and watch for spark.

Sorry yeah the igniter is known good (or was at least) and once the igniter was changed, the dash tacho was working again, and if we switch between the two igniters, the running of the car doesnt change, stil 2cyl, just the tacho works/doesnt.

Its pointing us towards the coil pack, but wanna make sure theres nothing that ive obviously missed software etc wise

Thats ^^^ how we deduced that 1 and 4 werent firing. Whatever we did, any combination of wires and plugs, whatever was connected to that side of the coil wouldnt spark (where 1+4 should be).

One other intresting thing was, with the orignal igniter, the revs on MT would be exactly half that of the tacho (when it worked). Now with the new igniter they match.

I did the same thing after I tried Joe's new spark out wiring. I swapped my coils around and the 2 non-firing cylinders moved so I knew it was one of my coils. I found a replacement for the blown coil for pretty cheap from a guy who parts Spec Miatas in Atlanta. He only had 1 so I only replaced the blown coil powering the two dead cylinders and I thought my other coil was fine since it continued to work. After I got MS up and running I turbo'd the car and I had a misfire at 3psi with new wires and new plugs gapped at .035. I gapped them down to .022 and the misfire moved to 6psi, but I still get it. I think my other coil (the one I didn't replace) was also damaged and is causing my misfire at this low boost setting. Just something to keep an eye out for down the road even if you replace the bad coil.

switch 1&4 with 2&3 and see if those two don't come back to life. Easy test.

As in just sawp leads round? Or you mean the actual coil? I wasnt aware you could actually the move 2 coils about? Is that done by unbolting the coil pack and then swapping the plugs underneath or.....?

nah, just move the spark plugs on either the plugs or coilpacks. you should get spark on 1&4 and now no spark on 2&3, if none of the coilpacks is actually dead. if no change, then it's the signal to the coilpack.

make sense?

Did you mean that? ^^^

maybe i did. basically you're just testing to see if one of the coilpacks is actually dead, or the input into it.

I had the same problem and it was the wire going from MS to the coil pack. I'm guessing the tach works off the signals going to to the igniter and if one batch isn't working, it only sees half the triggers, causing it to think the crank is going half as fast. I would swap the triggers or swap the coils so that the second output from MS (the one that's not working) is on the known good coil like (I think) Brain and Clay are saying. I think you can swap just the actual coil packs, but in my case it would be easier to just swap the wires coming from the MS.

Clay, did your tach go to half RPM when your coil died? If not, I would say it's wiring.

My tach on dash never went to half revs, my rev counter on MT did. My mate has another coil and igniter to try now, so fingers crossed!

TrickerZ, No my tach always worked fine, but I have a 96 and the coils don't feed the tach. I ended up swapping to a new coil pack and mine worked so I'm sure one of my coilpacks were dead.